Automated gesture recognition was the subject of considerable study from 1995-2001. An early objective of gesture recognition was to recognize sign languages, such as American Sign Language for the deaf. Gestures were processed based on a three-dimensional geometry of the human hand.
Another objective of gesture recognition was control of machines, as described in U.S. Pat. No. 5,594,469 to Freeman et al entitled HAND GESTURE MACHINE CONTROL SYSTEM. The approach used by Freeman et al. was to have a hand gesture cause movement of an on-screen displayed hand icon over an on-screen displayed machine control icon. The hand icon moves the machine control icon in accordance with sensed hand movements, to effectuate machine control. An advantage of this approach is that a user does not have to learn a set of gestures, but instead has to make a series of motion and adjust the motions using the hand icon.
In U.S. Pat. No. 6,002,808 to Freeman entitled HAND GESTURE CONTROL SYSTEM, and in Mitsubishi's published report TR-94 entitled TELEVISION CONTROL BY HAND GESTURES, hand gestures are sensed optically through use of a camera, and converted into a digital representation based on horizontal and vertical position of the hand, length and width of the hand, and orientation of the hand.
In U.S. Pat. No. 7,058,204 to Hildreth et al. entitled MULTIPLE CAMERA CONTROL SYSTEM, a multi-camera technology is described, whereby a person can control a screen by pointing a finger.